Results in epidemiology often are equivocal, and money can cloud science (see: tobacco companies vs. cancer researchers). Clear-cut cases are rare. Yet just such a case showed up one day in 1984 in the office of Harris Pastides, a recently appointed associate professor of epidemiology at the University of Massachusetts at Amherst.

A graduate student named James Stewart, who was working his way through school as a health and safety officer at Digital Equipment Corp., told Pastides there had been a number of miscarriages at the company’s semiconductor plant in nearby Hudson, Mass. Women, especially of childbearing age, filled an estimated 68 percent of the U.S. tech industry’s production jobs, and Stewart knew something few outsiders did: Making computer chips involved hundreds of chemicals. The women on the production line worked in so-called cleanrooms and wore protective suits, but that was for the chips’ protection, not theirs. The women were exposed to, and in some cases directly touched, chemicals that included reproductive toxins, mutagens, and carcinogens. Reproductive dangers are among the most serious concerns in occupational health, because workers’ unborn children can suffer birth defects or childhood diseases, and also because reproductive issues can be sentinels for disorders, especially cancer, that don’t show up in the workers themselves until long after exposure.

Digital Equipment agreed to pay for a study, and Pastides, an expert in disease clusters, designed and conducted it. Data collection was finished in late 1986, and the results were shocking: Women at the plant had miscarriages at twice the expected rate. In November, the company disclosed the findings to employees and the Semiconductor Industry Association, a trade group, and then went public. Pastides and his colleagues were heralded as heroes by some and vilified by others, especially in the industry.

SIA, representing International Business Machines Corp., Intel Corp., and about a dozen other top technology companies, established a task force, and its experts flew to Windsor Locks, Conn., to meet Pastides at a hotel near Bradley International Airport. It was Super Bowl Sunday, January 1987. “That was a day I remember being at a tribunal,” Pastides says. The atmosphere “bordered on hostility. I remember being shellshocked.” Soon after the meeting the panel formally concluded that the study contained “significant deficiencies,” according to internal SIA records. Nevertheless, facing public pressure, SIA’s member companies agreed to fund more research.

Scientists from the University of California at Davis designed one of the biggest worker-health studies in history, involving 14 SIA companies, 42 plants, and 50,000 employees. IBM opted out, hiring Johns Hopkins University to study its plants, because IBM executives said their facilities were safer than the others, recalls Adolfo Correa, one of the lead Johns Hopkins scientists.

In epidemiology, follow-up studies usually get bigger and tougher, and for that reason they often contradict one another. But by December 1992, something rare had happened. All three studies — all paid for by the industry — showed similar results: roughly a doubling of the rate of miscarriages for thousands of potentially exposed women. [more]